(transitive) To loosen, as something interlaced or knotted; to disengage the parts of.

(transitive) To free from fastening or from restraint; to let loose; to unbind.

To resolve; to unfold; to clear.

(intransitive) To become untied or loosed.

(programming, transitive) In the Perl programming language, to undo the process of tying, so that a variable uses default instead of custom functionality.